Catalyst for producing syndiotactic configuration styrene-based polymers

ABSTRACT

A catalyst for producing styrene-based polymers having mainly syndiotactic configuration which comprises (A) a titanium compound and (B) a contact product of a methyl group-containing organoaluminum compound and water, wherein the contact product (B) has a high magnetic field component of not more than 50% in the methyl proton signal region due to an aluminum-methyl group (Al-CH 3 ) bond as determined by the proton nuclear magnetic resonance absorption method.

This is a division of application Ser. No. 07/274,022 filed Nov. 21,1988 and now U.S. Pat. No. 4,978,730.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for producing styrene-basedpolymers and catalysts for use therein. More particularly, it isconcerned with a process for efficiently producing styrene-basedpolymers having mainly syndiotactic configuration and catalysts for usedtherein.

2. Description of the Related Art

Styrene-based polymers having a syndiotactic configuration, particularlythose with high syndiotactic configuration, have not been known althoughthose having an atactic or isotactic configuration are known.

The present inventors' group has succeeded in developing styrene-basedpolymers having stereostructure that is mainly syndiotactic (JapanesePatent Application Laid-Open Nos. 104818/1987 and 187708/1987).

The catalysts to be used in production of the above styrene-basedpolymers having mainly syndiotactic configuration are not only expensivebut also have insufficient activity.

Thus the present inventors made expensive investigations to develop aprocess whereby styrene-based polymers having syndiotactic configurationcan be produced more efficiently.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a process forefficiently producing styrene-based polymers with high syndiotacticity.

Another object of the present invention is to provide an economicallyadvantageous process for producing styrene-based polymers havingsyndiotactic configuration.

Still another object of the present invention is to provide a catalystsuitable for efficiently producing styrene-based polymers with highsyndiotacticity.

The present invention relates to a process for producing styrene-basedpolymers having mainly syndiotactic configuration by the use of acatalyst comprising (A) a titanium compound and (B) a contact product(reaction product) of a methyl group-containing organoaluminum compound(an organoaluminum compound containing methyl group) and water; whichprocess is characterized in that the contact product (B) has a highmagnetic field component of not more than 50% in a methyl proton signalregion due to an aluminum-methyl group (Al-CH₃) bond as determined bythe proton nuclear magnetic resonance absorption method.

The present invention further relates to a catalyst for producingstyrene-based polymers, containing the above components (A) and (B) asmain components.

DESCRIPTION OF PREFERRED EMBODIMENTS

The process of the present invention is carried out in the presence of acatalyst containing (A) a titanium compound and (B) a contact product ofa methyl group-containing organoaluminum compound and water as maincomponents.

Various titanium compounds can be used as component (A). An example ofthe titanium compounds is at least one compound selected from the groupconsisting of titanium compounds and titanium chelate compoundsrepresented by formula (I) or (II):

    TiR.sup.1.sub.a R.sup.2.sub.b R.sup.3.sub.c R.sup.4.sub.4-(a+b+c) (I)

    TiR.sup.1.sub.d R.sup.2.sub.e R.sup.3.sub.3-(d+e)          (II)

(wherein R¹, R², R³ and R⁴ represent independently a hydrogen atom, analkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20carbon atoms, an aryl group, an alkylaryl group, an aryl alkyl group andan aryloxy group each having 6 to 20 carbon atoms, an acyloxy grouphaving 1 to 20 carbon atoms, a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group or a halogen atom; a, b and care independently an integer of 0 to 4, and d and e are independently aninteger of 0 to 3).

R¹, R², R³ and R⁴ in general formula (I) or (II) independently ahydrogen atom, an alkyl group having 1 to 20 carbon atoms (e.g., amethyl group, an ethyl group, a propyl group, a butyl group, an amylgroup, an isoamyl group, an isobutyl group, an octyl group, or a2-ethylhexyl group), an alkoxy group having 1 to 20 carbon atoms (e.g.,a methoxy group, an ethoxy group, a propoxy group, a butoxy group, anamyloxy group, a hexyloxy group, or a 2-ethylhexyloxy group), an arylgroup, an alkylaryl group, an arylalkyl group and an aryloxy group eachhaving 6 to 20 carbon atoms (e.g., a phenyl group, a tolyl group, axylyl group, a benzyl group, or a phenoxy group), an acyloxy grouphaving 1 to 20 carbon atoms (e.g., a heptadecylcarbonyloxy group), acyclopentadienyl group, a substituted cyclopentadienyl group (e.g., amethylcyclopentadienyl group, a 1,2-dimethylcyclopentadienyl group, or apentamethylcyclopentadienyl group), an indenyl group, or a halogen atom(e.g., chlorine, bromine, iodine or fluorine). R¹, R², R³ and R⁴ may bethe same or different.

Specific examples of tetravalent titanium compounds and titanium chelatecompounds represented by general formula (I) are; methyltitaniumtrichloride, titanium tetramethoxide, titanium tetraethoxide, titaniumisopropoxytrichloride, titanium diisopropoxydichloride, titaniumtriisopropoxymonochloride, tetra(2-ethylhexyloxy)titanium,cyclopentadienyltitanium trichloride, biscyclopentadienyltitaniumdichloride, cyclopentadienyltitanium trimethoxide,cyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltitaniumtrimethoxide, pentamethylcyclopentadienyltrimethyltitanium, titaniumtetrachloride, titanium tetrabromide, bis(2,4-pentanedionate)titaniumoxide, bis(2,4-pentanedienate)titanium dichloride, andbis(2,4-pentanedionate)titanium dibutoxide. Other examples in which oneof R¹, R², R³ and R⁴ is a cyclopentadienyl group, a substitutedcyclopentadienyl group or an indenyl group are cyclopentadienyltitaniumtrimethyl, cyclopentadienyltitanium tributyl,pentamethylcyclopentadienyltitanium trimethyl,pentamethylcyclopentadienyltitanium triethyl,pentamethylcyclopentadienyltitanium tripropyl,pentamethylcyclopentadienyltitanium tributyl, cyclopentadienyltitaniummethyldichloride, cyclopentadienyltitanium ethyldichloride,pentamethylcyclopentadienyltitanium methyldichloride,pentamethylcyclopentadienyltitanium ethyldichloride,cyclopentadienyltitanium dimethylmonochloride, cyclopentadienyltitaniumdiethylmonochloride, cyclopentadienyltitanium trimethoxide,cyclopentadienyltitanium triethoxide, cyclopentadienyltitaniumtriisopropoxide, pentamethylcyclopentadienyltitanium trimethoxide,pentamethylcyclopentadienyltitanium triethoxide,pentamethylcyclopentadienyltitanium triisopropoxide,pentamethylcyclopentadienyltitanium trichloride,cyclopentadienyltitanium monomethoxydichloride, cyclopentadienyltitaniumdimethoxymonochloride, pentamethylcyclopentadienyltitaniummonomethoxydichloride, cyclopentadienyltitanium triphenoxide,cyclopentadienyltitanium diphenoxymonochloride, cyclopentadienyltitaniummonophenoxydichloride, cyclopentadienyltitanium tribenzyl,cyclopentadienyltitanium methyldibenzyl,pentamethylcyclopentadienyltitanium tribenzyl,pentamethylcyclopentadienyltitanium diethoxymethyl, indenyltitaniumtrichloride, indenyltitanium triumethoxide, indenyltitanium triethoxide,indeyltitanium trimethyl, and indenyltitanium tribenzyl. In addition, asthe titanium compound of component (A), condensed titanium compoundsrepresented by the general formula (III): ##STR1## (wherein R⁵ and R⁶represent independently a halogen atom, an alkoxy group having 1 to 20carbon atoms, or an acyloxy group having 1 to 20 carbon atoms, and k is2 to 20) may by used.

The above titanium compounds may be used in the form of complexes withesters, ethers and the like.

Typical examples of the trivalent titanium compound represented by thegeneral formula (II) as component (A) are titanium trihalides such astitanium trichloride, and cyclopentadienyltitanium compounds such ascyclopentadienyltitanium dichloride. In addition, those obtained byreducing tetravalent titanium compounds can be used. These trivalenttitanium compounds may be used in the form of complexes with esters,ethers and the like.

Component (B) of the catalyst to be used in the present invention is acontact product of a methyl group-containing organoaluminum compound andwater. This contact product is usually obtained by contacting orreacting a methyl group-containing organoaluminum compound with water.As the methyl group-containing organoaluminum compound, trialkylaluminumrepresented by the general formula:

    AlCH.sub.3 R'.sub.2                                        (IV)

(wherein R' is an alkyl group having 1 to 8 carbon atoms) is usuallyused. Specific examples of the trialkylaluminum are trimethylaluminum,methyldiethylaluminum, dimethylethylauminum, methyldiisobutylaluminum,and dimethylisobutylaluminum. Of these compounds, trimethylaluminum ismost preferred.

As the water to be condensed with the organoaluminum compound, thenormal water and ice, or various water-containing compounds, e.g.,solvents containing water, inorganic compounds containing water adsorbedthereon, and metal salts containing water of crystallization, such asCuSO₄.5H₂ O can be used.

The contact product (reaction product) of the methyl group-containingorganoaluminum compound and water includes various products, althoughthey are not always identified. For example, when the methylgroup-containing organoaluminum compound is trimethylaluminum, thecontact product contains chain-like methylaluminoxane represented by thegeneral formula: ##STR2## (wherein n is an integer of 2 to 50), andcyclic methylaluminoxane having a repeating unit represented by thegeneral formula: ##STR3## (degree of polymerization: 2 to 52).

In general, the contact product of the organoaluminum compound (e.g.,trialkylaluminum) and water contains various compounds, the type ofwhich varies depending on contacting conditions. For example, when theorganoaluminum compound is trialkylaluminum, the contact product is amixture of the aforementioned chain-like alkylaluminoxane (e.g.,chain-like methylaluminoxane) and cyclic alkylaluminoxane (e.g., cyclicmethylaluminoxane), unreacted trialkylaluminum, and other condensates,or a molecule resulting from association in a complicated manner of theabove mixture. Preferred as component (B) is a contact product oftrialkylaluminum (preferably trimethylaluminum) and water in which thearea of the high magnetic field component in the methyl proton signalregion due to the aluminum-methyl group (Al-CH₃) bond as observed by theproton nuclear magnetic resonance method is not more than 50% of thetotal signal area.

In a proton nuclear magnetic resonance (¹ H-NMR) spectral analysis of asolution of the contact product in toluene at room temperature, themethyl proton signal due to Al-CH₃ is observed in the region of 1.0 to-0.5 ppm (tetramethylsilane (TMS) standard). Since the proton signal ofTMS (0 ppm) is in the 1.0 to -0.5 ppm region of the methyl proton signaldue to Al-CH₃, the contact product is measured with toluene as thesolvent as the standard. The methyl proton signal due to Al-CH₃ isdivided into two components: the high magnetic field component in the-0.1 to -0.5 ppm region and the other magnetic field component in the1.0 to -0.1 ppm region. In contact products preferably used as component(B), the area of the high magnetic field component is not more than 50%,preferably 45 to 5% of the total signal area in the 1.0 to -0.5 ppmregion.

If the high magnetic field component is more than 50%, the resultingcatalyst has insufficient activity and thus styrene-based polymershaving syndiotactic configuration cannot be produced efficiently.

There are no special limitations to methods of preparing the contactproduct of the methyl group-containing organoaluminum compound andwater; that is, the contact product can be obtained by known methods.For example, (1) a method in which the methyl group-containingorganoaluminum compound is dissolved in an organic solvent and thencontacted with water, (2) a method in which the methyl group-containingorganoaluminum compound is first added at the time of polymerizationand, thereafter, water is added, and (3) a method in which the methylgroup-containing organoaluminum compound is contacted with water ofcrystallization contained in metal salts and the like, or with waterabsorbed in inorganic or organic compounds can be employed. The abovewater may contain up to about 20% by weight ammonia, amines such asethylamine, sulfur compounds (e.g., hydrogen sulfide), phosphoruscompounds (e.g., phosphorous acid esters), and the like.

Contacting conditions for making the high magnetic field component notmore than 50% are varied and cannot be always specified. In general, thecontact reaction is preferably carried out under such conditions that(1) the contact reaction temperature is raised (specifically about 40°to 80° C.), (2) the ratio of water to the methyl group-containingorganoaluminum compound is increased (specifically, water/methylgroup-containing organoaluminum compound=1.2/1 to 5/1 (molar ratio)),and (3) heat treatment is carried out after the contact reaction.

In preparation of the above contact product, the aforementionedorganoaluminum compound is used. Particularly in the case oftrimethylaluminum, it may be used in combination with branchedalkylaluminum represented by the general formula: AlR₃ (wherein R, whichmay be identical or different, is a branched alkyl group having 3 to 10carbon atoms). In the above formula, R is a branched alkyl group having3 to 10 carbon atoms, e.g., an isopropyl group, an isobutyl group, asec-butyl group, a tert-butyl group, an isopentyl group, a neopentylgroup, a 2-methylpenthyl group, a 2-methylhexyl group, and a2-ethylhexyl group. Specific examples of the tribranched alkylaluminumare triisopropylaluminum, triisobutylaluminum, tri-tert-butylaluminum,triisopentylaluminum, tri(2-methylpentyl) aluminum,tri(2-methylhexyl)aluminum, tri(2-ethylhexyl) aluminum and the like. Ofthese compounds, triisobutylaluminum is preferred.

In preparation of the contact product as component (B),trimethylaluminum and the above tri-branched alkylaluminum can be usedin varied ratios when they are used in combination. In general, themolar ratio of trimethylaluminum to tri-branched alkylaluminum is99.9:0.1 to 50:50 and preferably 98:2 to 72:25.

The contact product as component (B) has varied molecular weight. Anycontact product can be used in the process of the present invention. Ofthese contact products, those having a molecular weight of 400 to 3,000,preferably 500 to 2200, most preferably 600 to 1800 as determined by thefreezing point depression method using benzene as a solvent, are used.

The above contact product, when used as such as component (B) of thecatalyst, exhibits sufficiently high activity. Heat treatment after thecontact reaction between the organoaluminum compound and water furtherincreased the catalytic activity. More specifically, after the contactreaction between the organoaluminum compound and water, a solid residue(e.g., water-containing compounds) is filtered off and the filtrate isheated under atmospheric pressure or reduced pressure at a temperatureof 30° to 200° C., preferably 40° to 170° C., most preferably 70° to150° C. for 20 minutes to 8 hours, preferably 0.5 to 5 hours. In heattreatment, the temperature is usually chosen appropriately within therange stated above. If the temperature is less than 30° C., insufficientimprovement due to heat results. On the other hand, if it is more than200° C., undesirable heat decomposition of the contact product itselfoccurs.

Depending on heat treating conditions, the contact product obtained iscolorless solid or solution. The product thus obtained is, if necessary,dissolved in or diluted with a hydrocarbon solvent and can be used as acatalyst solution.

The catalyst of the present invention contains the above components (A)and (B) as main components. If necessary, the catalyst may furthercontain other catalyst components, e.g., other organometallic compounds.The ration of component (A) to component (B) in the catalyst is variedand cannot be determined unconditionally. The ratio of aluminumcontained component (B) to titanium contained in component (A), i.e.,aluminum/titanium (molar ratio) is 1:1 to 1×10⁶ :1 and preferably 10:1to 1×10⁴ :1.

In the present invention, along with components (A) and (B), anorganoaluminum compound (C) can be used as a main component of thecatalyst.

As component (C), various organoaluminum compounds can be used. Morespecifically, organoaluminum compounds represented by the generalformula:

    R.sup.7.sub.k Al(OR.sup.8).sub.m H.sub.p X.sup.2.sub.q     (VII)

(wherein R⁷ and R⁸ are independently an alkyl group having 1 to 8 carbonatoms, preferably 1 to 4 carbon atoms, X² is a halogen atom, k is 0<k≦3,m is 0<m≦3, p is 0≦p <3, q is 0≦q<3, and k+m+p+q=3) can be used.

Examples of the organoaluminum compound represented by the generalformula (VII) are shown below. p=q=0

Compounds represented by the general formula:

    R.sup.7.sub.k Al(OR.sup.8).sub.3-k

(wherein R⁷ and R⁸ are the same as above, and k is preferably a numberof 1.5≦k <3). m=p=0

Compounds represented by the general formula:

    R.sup.7.sub.k AlX.sup.2.sub.3-k

(wherein R⁷ and X¹ are the some as above, and k is preferably 0<k <3).m=q=0

Compounds represented by the general formula:

    R.sup.7.sub.k AlH.sub.3-k

(wherein R⁷ is the same as above, and k is preferably 2≦k<3). p=0

Compounds represented by the general formula:

    R.sup.7.sub.k Al(OR.sup.8).sub.m X.sup.2.sub.q

(wherein R⁷, R⁸ and X² are the same as above, and 0<k≦3, 0≦m<3, 0≦q<3and k+m+q=3). p=q=0, k=3

Trialkylaluminum such as triethylaluminum and tributylaluminum. Ofthese, triethylaluminum, tri-n-butylaluminum and triisobutylaluminum arepreferred. p=q=0, 1.5≦k<3

Dialkylaluminumalkoxide such as diethylaluminum ethoxide anddibutylaluminum butoxide, alkylaluminum sesquialkoxide such asethylaluminum sesquiethoxide and butylaluminum sesquibutoxide, andpartially alkoxylated alkylaluminum having an average compositionrepresented by the formula: R⁷ ₂.5 Al(OR⁸)₀.5, for example. m=p=0

Partially halogenated alkylaluminum, e.g., dialkylaluminum halogenide(k=2), such as diethylaluminum chloride, dibutylaluminum chloride anddiethylaluminum bromide, alkylaluminum sesquihalogenide (k=1.5), such asethylaluminum sesquichloride, butylaluminum sesquichloride andethylaluminum sesquihalogenide, and alkylaluminum dihalogenide (k=1),such as ethylaluminum dichloride, propylaluminum dichloride andbutylaluminum dibromide. m=q=0

Partially hydrogenated alkylaluminum, e.g., dialkylaluminum hydride(k=2), such as diethylalumnum hydride and dibutylaluminum hydride, andalkylaluminum dihydride (m=k), such as ethylaluminum dihydride andpropylaluminum dihydride. p=0

Partially alkoxylated and halogenated alkylaluminum, e.g., ethylaluminumethoxychloride, butylaluminum butoxychloride and ethylaluminumethoxybromide (k=m=q=1).

The catalyst of the present invention contains the above components (A),(B) and (C) as main components. If necessary, the catalyst may containother catalyst components.

The ratio of component (A), component (B) and component (C) in thecatalyst is varied and cannot be determined unconditionally. The ratioof aluminum contained in components (B) and (C) to titanium contained incomponent (A), i.e., aluminum/titanium (molar ratio) is 1:1 to 1:1×10⁴and preferably 10:1 to 1×10³ :1.

The catalyst of the present invention is highly active in producingstyrene-based polymers having mainly syndiotactic configuration.

In accordance with the process of the present invention, styrene-basedmonomers such as styrene and/or styrene derivatives (e.g., alkylstyrene,alkoxystyrene, halogeneted styrene, and vinyl benzoate) are polymerizedor copolymerized in the presence of a catalyst containing components (A)and (B), or components (A), (B) and (C) as main components to producestyrene-based polymers. This polymerization may be bulk polymerizationor may be carried out in a solvent, e.g., aliphatic hydrocarbon such aspentane, hexane and heptane, or aromatic hydrocarbon such as benzene,toluene and xylene. The polymerization temperature is not critical, andit is usually -30° to 120° C. and preferably -10° to 100° C.

Styrene-based polymers produced by the above process have mainlysyndiotactic configuration. The styrene-based polymers having mainlysyndiotactic configuration mean styrene-based polymers having astereostructure that is mainly syndiotactic, i.e., a stereostructure inwhich phenyl groups or substituted phenyl groups as side chains arelocated alternately at opposite positions relative to the main chaincomposed of carbon-carbon bonds. The tacticity is quantitativelydetermined by the nuclear magnetic resonance method using carbon isotope(¹³ C-NMR method). The tacticity determined by the ¹³ C-NMR method isindicated in terms of proportions of structural units continuouslyconnected to each other, i.e., diad in which two structural units areconnected to each other, triad in which three structural units areconnected to each other, and pentad in which five structural units areconnected to each other. The styrene-based polymers having mainlysyndiotactic configuration of the present invention includespolystyrene, poly(alkylstyrene), poly(halogenated styrene).poly(alkoxystyrene), polyvinyl benzoate, or mixtures thereof andcopolymers containing the above monomers as main components, each havingsuch a syndiotactic structure that the proportion of diad is at least75% and preferably at least 85%, or the proportion of pentad (racemipentad) is at least 30% and preferably at least 50%.

The poly(alkylstyrene) includes polymethylstyrene, polyethylstyrene,polyisopropylstyrene, and poly(tert-butylstyrene). The poly(halogenatedstyrene) includes polychlorostyrene, polybromostyrene, andpolyfluorostyrene. The poly(alkoxystyrene) includes polymethoxystyreneand polyethoxystyrene. Particularly preferred among the above polymersare polystyrene, poly(p-methylstyrene), poly(m-methylstyrene),poly(p-tert-butylstyrene), poly(p-chlorostyrene), poly(m-chlorostyrene),poly(p-fluorostyrene), and a copolymer of styrene and p-methylstyrene.

The styrene-based polymers produced according to the process of thepresent invention have a weight average molecular weight of at least5,000 and preferably 10,000 to 20,000,000 and a number average molecularweight of at least 2,500 and preferably 5,000 to 10,000,000.

The styrene-based polymers produced by the process of the presentinvention have sufficiently high syndiotacticity. If de-ashing treatmentusing a washing solution containing hydrochloric acid and the like isapplied after polymerization, washing treatment is further applied usinga solvent (e.g., methyl ethyl ketone) after the process of washing anddrying in vacuum to remove a soluble portion, and the insoluble portionis treated with, for example, chloroform, styrene-based polymers havinga much higher syndiotacticity can be obtained efficiently.

By controlling the catalyst components, the molecular weight of thestyrene-based polymer can be controlled within the desired range.

Heat treatment of the contact product as component (B) further increasesthe catalytic activity and thus the desired styrene-based polymers canbe produced even more increased efficiently.

Styrene-based polymers having syndiotactic configuration are excellentin physical properties such as heat resistance and chemical resistance,and thus can be widely used in various applications.

The present invention is described in greater detail with reference tothe following examples.

EXAMPLE 1

(1) Preparation of Contact Product of Trimethylaluminum and Water

In a 500-milliliter glass vessel which had been purged with argon wereplaced 200 ml of toluene, 17.8 g (71 mmol) of copper sulfatepentahydrate (CuSO₄.5H₂ O) and 24 ml (250 mmol) of trimethylaluminum,which were then reacted at 40° C. for 8 hours. Then, solids wereseparated from the reaction mixture, and the toluene was distilled awayfrom the solution as obtained above under reduced pressure at roomtemperature to obtain 6.7 g of a contact product. The molecular weightof the contact product as determined by the freezing point depressionmethod was 610. The high magnetic field component (i.e., -0.1 to -0.5ppm) as determined by the ¹ H-NMR method was 43%.

(2) Production of Styrene-Based Polymer

In a 500-milliliter reactor were placed 100 ml of toluene, 15 mmol asaluminum atom of the contact product obtained in (1) above, 0.025 mmolof cyclopentadienyltitanium trichloride and 150 mmol of styrene, andpolymerization was performed at 50° C. for one hour. After thepolymerization, the product was washed with a mixture of hydrochloricacid and methanol to decompose the catalyst components (i.e., thecontact product and cyclopentadienyltitanium trichloride) and then driedto obtain 5.0 g of syndiotactic polystyrene (syndiotacticity in racemipentad: 98%) (yield: 32.1%).

EXAMPLE 2

(1) Preparation of Contact Product of Trimethylaluminum and Water

The procedure of Example 1 (1) was repeated with the exception that thereaction time was changed to 24 hours, to obtain 6.2 g of a contactproduct having a molecular weight of 750 and a high magnetic componentof 41%.

(2) Production of Styrene-Based Polymer

The procedure of Example 1 (2) was repeated with the exception that thecontact product obtained in (1) above was used, to obtain 6.6 g ofsyndiotactic polystyrene (syndiotacticity in recemi pentad: 98%) (yield:42.2%).

EXAMPLE 3

(1) Preparation of Contract Product of Trimethylaluminum and Water

The procedure of Example 1 (1) was repeated with the exception that 22.9g (91 mmol) of copper sulfate pentahydrate (CuSO₄.5H₂ O) and 100 ml oftoluene were used, and the reaction time was changed to 24 hours, toobtain 7.0 g of a contact product having a molecular weight of 1,000 anda high magnetic field component of 33%.

(2) Production of Styrene-Based Polymer

The procedure of Example 1 (2) was repeated with the exception that thecontact product obtained in (1) above was used, to obtain 7.4 g ofsyndiotactic polystyrene (syndiotacticity in racemi pentad: 98%) (yield:47.4%).

EXAMPLE 4

(1) Preparation of Contact Product of Trimethylaluminum and Water

The procedure of Example 1 (1) was repeated with the exception that 25.2g (100 mmol) of copper sulfate pentahydrate (CuSO₄.5H₂ O) was used andthe reaction time was changed to 15 hours, to obtain 6.5 g of a contactproduct having a molecular weight of 850 and a high magnetic fieldcomponent of 28%.

(2) Production of Styrene-Based Polymer

The procedure of Example 1 (2) was repeated with the exception that thecontact product obtained in (1) above was used, to obtain 11.0 g ofsyndiotactic polystyrene (syndiotacticity in racemi pentad: 98%) (yield:70.5%).

COMPARATIVE EXAMPLE 1

(1) Preparation of Contact Product of Trimethylaluminum and Water

The procedure of Example 1 (1) was repeated with the exception that 34.6ml (360 mmol) of trimethylaluminum and 29.4 g (117 mmol) of coppersulfate pentahydrate (CuSO₄.5H₂ O) were used, and the reaction time waschanged to 3 hours, to obtain 3.2 g of a contact product having amolecular weight of 470 and a high magnetic field component of 65%.

(2) Production of Styrene-Based Polymer

The procedure of Example 1 (2) was repeated with the exception that thecontact product obtained in (1) above was used. In this case, only 0.01g of syndiotactic polystyrene (syndiotacticity in racemi pentad: 96%)was obtained (yield: 0.1%).

EXAMPLE 5

In a 500-milliliter reactor were placed 200 ml of heptane, 8 mmol asaluminum atom of the contact product obtained in Example 1 (1), 0.08mmol of pentamethylcyclopentadienyltitanium trimethoxide and 50 ml ofstyrene, and polymerization was performed at 50° C. for 2 hours. Afterthe polymerization, the product was washed with a mixture ofhydrochloric acid and methanol mixture to decompose the catalystcomponents and then dried to obtain 25.0 g of a polymer. This polymerwas extracted with methyl ethyl ketone by the use of a Soxhlet extractorto obtain a methyl ethyl ketone-insoluble portion (MIP) of 98.0%. Thepolymer thus obtained had a weight average molecular weight of 1,600,000and a number average molecular weight of 662,000. From the melting pointand the results of the ¹³ C-NMR analysis, it was confirmed that thepolymer was polystyrene having syndiotactic configuration.

EXAMPLE 6

The procedure of Example 5 was repeated with the exception thatpentamethylcyclopentadienyltitanium triethoxide was used in place of thepentamethylcyclopentadienyltitanium trimethoxide, to obtain syndiotacticpolystyrene having a weight average molecular weight of 1,620,000 in aconversion of 44.7%.

EXAMPLE 7

The procedure of Example 5 was repeated with the exception thatpentamethylcyclopentadienyltitanium di-tert-butoxy monochloride was usedin place of the pentamethylcyclopentadienyltitanium trimethoxide, toobtain syndiotactic polystyrene having a weight average molecular weightof 1,480,000 in a conversion of 16.9%.

EXAMPLE 8

The procedure of Example 5 was repeated with the exception that thecontact product obtained in Example 2 (1) was used andcyclopentadienyltitanium trimethoxide was used in place of thepentamethylcyclopentadienyltitanium trimethoxide, to obtain syndiotacticpolystyrene having a weight average molecular weight of 128,000 in aconversion of 75.2%.

EXAMPLE 9

Syndiotactic polystyrene was produced in the same manner as in Example 8except that cyclopentadienyltitanium triethoxide was used in place ofthe cyclopentadienyltitanium trimethoxide (conversion: 68.6%).

EXAMPLE 10

Syndiotactic polystyrene was produced in the same manner as in Example 8except that cyclopentadienyltitanium triphenoxide was used in place ofthe cyclopentadienyltitanium trimethoxide (conversion: 60.3%).

COMPARATIVE EXAMPLE 2

The procedure of Example 5 was repeated with the exception that thecontact product obtained in Comparative Example 1 (1) was used andtitanium tetraethoxide was used in place of thepentamethylcyclopentadienyltitanium trimethoxide. In this case,syndiotactic polystyrene was obtained only in a conversion of 6.6%.

The conversion, yield, methyl ethyl ketone-insoluble portion (MIP) andweight average molecular weight (Mw) of syndiotactic polystyrenesobtained in Examples 5 to 10 and Comparative Example 2 are shown inTable 1.

                  TABLE 1                                                         ______________________________________                                                    Conversion                                                                              Yield     MIP  Mw                                       No.         (%)       (g)       (%)  (×10.sup.4)                        ______________________________________                                        Example 5   55.0      25.0      98   160                                      Example 6   44.7      20.3      95   162                                      Example 7   16.9       7.7      96   148                                      Example 8   75.2      34.2      86   12.8                                     Example 9   68.6      31.2      88   19.4                                     Example 10  60.3      27.4      94   11.8                                     Comparative  6.6       3.0      88.2 54.1                                     Example 2                                                                     ______________________________________                                    

EXAMPLE 11 TO 14

In a 500-milliliter reactor were placed 200 ml of heptane, 8 mmol asaluminum atom of the contact product obtained in Example 1 (1), 0.08mmol of a titanium compound as shown in Table 2 and 50 ml of styrene,and polymerization was performed at 50° C. for 2 hours. After thepolymerization, the reaction product was washed with a mixture ofhydrochloric acid and methanol to decompose the catalyst components andthen dried to obtain a polymer. This polymer was extracted with methylethyl ketone by the use of a Soxhlet extractor. The methyl ethylketone-insoluble portion (MIP) was 98.0%. The polymer had a weightaverage molecular weight of 1,450,000 and a number average molecularweight of 662,000. From the melting point and the results of the ¹³C-NMR analysis, it was confirmed that the polymer was polystyrene havingsyndiotactic configuration.

The conversion, yield, methyl ethyl ketone-insoluble portion (MIP),weight average molecular weight (Mw) and number average molecular weight(Mn) of polystyrenes obtained in Examples 11 to 14 are shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________           Titanium Conversion                                                                          Yield                                                                             MIP    Mn                                           No.    Compound (%)   (g) (%)                                                                              Mw  (×10.sup.4)                            __________________________________________________________________________    Example 11                                                                           Cp*TiMe.sub.3                                                                          90.7  41.2                                                                              98.0                                                                             145 62.2                                         Example 12                                                                           Cp*TiEt.sub.3                                                                          83.1  37.8                                                                              97.1                                                                             128 52.3                                         Example 13                                                                           Cp*Ti(n-Bu).sub.3                                                                      75.2  34.8                                                                              96.9                                                                             115 54.5                                         Example 14                                                                           Cp*Ti(CH.sub.2 C.sub.6 H.sub.5).sub.3                                                  50.7  23.0                                                                              97.5                                                                             106 42.7                                         Comparative                                                                          Ti(OEt).sub.4                                                                           6.6   3.0                                                                              88.2                                                                             54.1                                                                              20.6                                         Example 2                                                                     __________________________________________________________________________     *Cp = pentamethylcyclopentadienyl                                        

EXAMPLE 15

In a 500-milliliter reactor were placed 200 ml of heptane, 2 mmol asaluminum atom of the contact product obtained in Example 1 (1), 2 mmolof tirisobutylaluminum, 0.08 mmol of pentamethylcyclopentadienyltitaniumtrimethoxide and 50 ml of styrene, and polymerization was performed at50° C. for 2 hours. After the polymerization, the product was washedwith a mixture of hydrochloric acid and methanol to decompose thecatalyst components and then dried to obtain 41.2 g of a polymer. Thispolymer was extracted with trimethyl ethyl ketone by the use of aSoxhlet extractor. The methyl ethyl ketone-insoluble portion (MIP) was98.0%. The polymer had a weight average molecular weight of 850,000 anda number average molecular weight of 369,000. From the melting point andthe results of the ¹³ C-NMR analysis, it was confirmed that the polymerwas polystyrene having syndiotactic configuration.

EXAMPLE 16

Polystyrene having syndiotactic configuration was produced in the samemanner as in Example 15 except that 2 mmol of triethylaluminum was usedin place of the triisobutylaluminum.

EXAMPLE 17

Polystyrene having syndiotactic configuration was produced in the samemanner as in Example 15 except that 2 mmol of monoethoxydiethylaluminumwas used in place of the triisobutylaluminum.

The catalyst compositions used and the results of polymerization inExample 15 to 17 are shown in Table 3.

EXAMPLES 18 TO 21

Polystyrene having syndiotactic configuration was produced in the samemanner as in Example 15 except that the conditions shown in Table 3 wereused. The results are shown in Table 3.

EXAMPLE 22

(1) Preparation of Contact Product of Trimethylaluminum and Water

In 200 ml of toluene as a solvent, 24.0 ml (0.250 mol) oftrimethylaluminum and 23.7 g (0.095 mol) of copper sulfate pentahydratewere reacted at 20° C. for 24 hours, and then solids were removed toobtain a toluene solution containing 8.1 g of methylaluminoxane as acontact product. In this contact product, the high magnetic fieldcomponent (i.e., 0.1 to -0.5 ppm) as determined by the ¹ H-NMR analysiswas 48%.

(2) Production of Styrene-Based Polymer

Polystyrene having syndiotactic configuration was produced in the samemanner as in Example 15 except that the contact product obtained in (1)above was used. The results are shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________                         Organoaluminum                                                          Contact*.sup.4                                                                      Compound                                                       Titanium Product     Amount                                                                             Conversion                                                                          MIP                                                                              Mw                                   No.   Compound (mmol)                                                                              Type  (mmol)                                                                             (%)   (%)                                                                              (×10.sup.4)                    __________________________________________________________________________    Example 15                                                                          Pcp*.sup.1 Ti(OMe)3                                                                    2     Al(i-Bu).sub.3                                                                      2    73    98 85                                   Example 16                                                                          Pcp*.sup.1 Ti(OMe).sub.3                                                               2     Al(Et).sub.3                                                                        2    64    96 90                                   Example 17                                                                          Pcp*.sup.1 Ti(OMe).sub.3                                                               2     Al(OEt)Et.sub.2                                                                     2    66    97 95                                   Example 18                                                                          Pcp*.sup.1 Ti(OEt).sub.3                                                               2     Al(Et).sub.2 Cl                                                                     2    54    97 84                                   Example 19                                                                          Cp*.sup.2 Ti(OMe).sub.3                                                                2     Al(i-Bu).sub.3                                                                      2    85    98 30                                   Example 20                                                                          Ind*.sup.3 Ti(OMe).sub.3                                                               2     Al(i-Bu).sub.3                                                                      2    68    98 52                                   Example 21                                                                          Pcp*.sup.1 TiCl(OMe).sub.2                                                             2     Al(i-Bu).sub.3                                                                      2    72    98 124                                  Example 22                                                                          Pcp*.sup.1 Ti(OMe).sub.3                                                               2     Al(i-Bu).sub.3                                                                      2    79    98 88                                   __________________________________________________________________________     *.sup.1 Pcp = pentamethylcyclopentadienyl                                     *.sup.2 Cp = cyclopentadienyl                                                 *.sup.3 Ind = indenyl                                                         *.sup.4 Containing methylaluminoxane as a main component.                

EXAMPLE 23

(1) Preparation of Contact Product of Aluminum Compound and Water(Component (B))

In a 500-milliliter glass vessel which had been purged with argon wereplaced 200 ml of toluene, 23.7 g (95 mmol) of copper sulfatepentahydrate (CuSO₄.5H₂ O) and 24 ml (250 mmol) of trimethylaluminum,which were then reacted at 40° C. for 30 hours. Then, solids wereremoved from the reaction mixture, and volatile components weredistilled away from the resulting solution under reduced pressure toobtain 7.04 g of a contact product. The molecular weight of the contactproduct as determined by the freezing point depression method was 1,100.In the contact product, the high magnetic filed component (i.e., -0.1 to-0.5 ppm) as determined by the ¹ H-NMR method was 30%.

(2) Production of Styrene-Based Polymer

In a 500-milliliter reactor were placed 50 ml of toluene, 10 mmol asaluminum atom of the contact product obtained in (1) above, 0.1 mmol oftetraethoxytitanium and 200 ml of styrene, and polymerization wasperformed at 50° C. for one hour. After the polymerization, the reactionproduct was washed with a mixture of hydrochloric acid and methanol todecompose the catalyst components and then dried to obtain 32.7 g of apolymer. This polymer was extracted with methyl ethyl ketone by the useof a Soxhlet extractor to obtain an extraction residue (polymer). Thepolymer as the extraction residue had a weight average molecular weightof 600,000 and a number average molecular weight of 300,000.

From the melting point and the results of the ¹³ C-NMR analysis, it wasconfirmed that the polymer was polystyrene having syndiotacticity inracemi pentad of 98%.

EXAMPLE 24

(1) Preparation of Contact Product of Aluminum Compound and Water(Component (B))

The procedure of Example 23 (1) was repeated with the exception that thereaction temperature and the reaction time were changed to 60° C. and 24hours, respectively, to obtain 6.5 g of a contact product. The molecularweight of the contact product as determined by the freezing pointdepression method was 1,900.

In the contact product, the high magnetic field component (i.e., -0.1 to-0.5 ppm) as determined by the ¹ H-NMR analysis was 29%.

(2) Production of Styrene-Based Polymer

The procedure of Example 23 (2) was repeated with the exception that 6mmol as aluminum atom of the contact product obtained in (1) above wasused, 0.06 mmol of pentamethylcyclopentadienyltitanium trimethoxide wasused in place of the tetraethoxytitanium, and the reaction temperaturewas changed to 70° C., to obtain 37.9 g of a polymer. Thesyndiotacticity in racemi pentad of the polymer as the extractionresidue was 97%. The polymer had a weight average molecular weight of1,800,000 and a number average molecular weight of 900,000.

EXAMPLE 25

In a 500-milliliter reactor were placed 50 ml of toluene, 3 mmol asaluminum atom of the contact product (molecular weight: 1,900) obtainedin Example 24 (1), 3 mmol of triisobutylaluminum, 0.06 mmol ofpentamethylcyclopentadienyltitanium trimethoxide and 200 ml of styrene,and polymerization was performed at 70° C. for one hour. Thereafter, thesame procedure as in Example 23 (2) was conducted to obtain 36.1 g of apolymer. For the polymer as the extraction residue, the syndiotacticityin racemi pentad was 95%, the weight average molecular weight was800,000, and the number average molecular weight was 400,000.

EXAMPLE 26

In a 500-milliliter reactor were placed 50 ml of toluene, 3 mmol asaluminum atom of the contact product (molecular weight: 1,900) obtainedin Example 24 (1), 3 mmol of triisobutylaluminum, 0.06 mmol ofpentamethylcyclopentadienyltitanium trimethoxide and 200 ml of styrene,and polymerization was performed at 70° C. for one hour. Thereafter, thesame procedure as in Example 23 (2) was conducted to obtain 36.1 g of apolymer. For the polymer as the extraction residue, the syndiotacticityin racemi pentad was 97%, the weight average molecular weight was400,000, and the number average molecular weight was 200,000.

EXAMPLE 27

In a 500-milliliter reactor were placed 50 ml of toluene, 6 mmol asaluminum atom of the contact product (molecular weight: 1,100) obtainedin Example 23 (1), 0.06 mmol of pentamethylcyclopentadienyltitaniumtrimethyl and 200 ml of styrene, and polymerization was carried out at70° C. for one hour. Thereafter, the same procedure as in Example 23 (2)was conducted to obtain 48.0 g of a polymer. For the polymer as theextraction residue, the syndiotacticity in racemi pentad was 98%, theweight average molecular weight was 1,200,000, and the number averagemolecular weight was 600,000.

EXAMPLE 28

(1) Preparation of Contact Product of Aluminum Compound and Water

In a 500-milliliter glass vessel which had been purged with argon wereplaced 200 ml of toluene, 23.7 g (95 mmol) of copper sulfatepentahydrate, 21.6 ml (225 mmol) of trimethylaluminum and 6.3 ml (25mmol) of triisobutylaluminum, which were then reacted at 40° C. for 24hours.

Then, solids were removed from the reaction mixture. The resultingsolution was subjected to heat treatment under reduced pressure at 110°C. for 2 hours to obtain 6.12 g of a colorless solid (contact product).The solid was dissolved in 50 ml of toluene to prepare a catalystsolution.

In the contact product, the high magnetic field component (i.e., -0.1 to-0.5 ppm) as determined by the ¹ H-NMR method was 31%.

(2) Polymerization of Styrene

In a 500-milliliter reactor were placed 25 ml of heptane, 6 mmol asaluminum atom of the contact product obtained in (1) above, 12×10⁻³ mmolof pentamethylcyclopentadienyltitanium trimethoxide and 225 ml ofstyrene, and polymerization was carried out at 70° C. for 3 hours.

After the polymerization, the product was washed with a mixture ofhydrochloric acid and methanol to decompose the catalyst components andthen dried to obtain 48.1 g of a polymer. The polymerization activitywas 297 g/g Al. The syndiotacticity in racemi pentad of the polymer asdetermined by the ¹³ C-NMR method was 96%.

EXAMPLE 29 TO 31

(1) Preparation of Contact Product of Aluminum Compound and Water

A contact product was prepared in the sam manner as in Example 28 (1)except that the amount of trimethylaluminum was changed, and an aluminumcompound in the amount shown in Table 4 was used in place of 6.3 ml (25mmol) of triisobutylaluminum, and then dissolved in toluene to prepare acatalyst solution.

In the contact products thus obtained, the high magnetic field component(i.e., -0.1 to -0.5 ppm) was 20% in Example 29, 18% in Example 30 and15% in Example 31.

A polymer (polystyrene) was produced in the same manner as in Example 28(2) except that the catalyst solution obtained in (1) above was used.The results are shown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________                Other Aluminum                                                                              Yield of                                            Trimethyl-  Compound      Contact                                                   aluminum       Amount                                                                             Product                                                                            Yield of                                                                           Activity                                                                            Syndiotacticity                     No. 1 (mmol)                                                                              Type     (mmol)                                                                             (g)  Polymer                                                                            (g/g · Al)                                                                 (%)                                 __________________________________________________________________________    Example 28                                                                          225   Triisobutyl-                                                                           25   6.12 48.1 297   96                                              aluminum                                                          Example 29                                                                          200   Triisobutyl-                                                                           50   7.09 50.8 314   95                                              aluminum                                                          Example 30                                                                          238   Triisobutyl-                                                                           12.5 5.97 45.0 278   98                                              aluminum                                                          Example 31                                                                          225   Tri(2-methyl-                                                                          25   7.62 49.3 304   97                                              pentyl)aluminum                                                   __________________________________________________________________________

EXAMPLE 32

(1) Preparation of Aluminoxane Subjected to Heat Treatment

In a 1,000-milliliter glass vessel which had been purged with argon wereplaced 74 g (0.30 mol) of copper sulfate pentahydrate (CuSO₄.5H₂ O), 500ml of toluene and 74 ml (0.78 mol) of trimethylaluminum, which were thenreacted at 20° C. for 30 hours. Then, solids were removed from thereaction mixture, and the solution thus obtained was subjected to heattreatment under reduced pressure at 110° C. for 2 hours. As a result,17.7 g of a colorless glassy contact product (aluminoxane) was obtained.

This contact product was dissolved in 50 ml of toluene to prepare acatalyst component.

In the contact product, the high magnetic field component (i.e., -0.1 to-0.5 ppm) was 39%.

(2) Polymerization of Styrene

In a 500-milliliter reactor were placed 200 ml of heptane, 6 mmol asaluminum atom of the aluminoxane obtained in (1) above, 0.06 mmol ofpentamethylcyclopentadienyltitanium trimethoxide and 50 ml of styrene,and polymerization was carried out 70° C. for one hour.

After the polymerization, the product was washed with a mixture ofhydrochloric acid and methanol to decompose the catalyst components andthen dried to obtain 9.86 g of a polymer (polystyrene). Thesyndiotacticity in racemi pentad of the polymer as determined by the ¹³C-NMR method was 98%.

EXAMPLE 33 TO 35

Catalyst components were obtained in the same manner as in Example 32(1) except that the heat treatment was performed under conditions shownin Table 5.

Thereafter, a polymer (polystyrene) was obtained in the same manner asin Example 32 (2) except that the above catalyst component was used. Theresults are shown in Table 5.

                                      TABLE 5                                     __________________________________________________________________________    Heat Treatment       Yield of                                                                             Yield of                                                     Temperature                                                                          Time                                                                             Aluminoxane                                                                          Polymer                                                                            Syndiotacticity                              No.   Pressure                                                                           (°C.)                                                                         (hr)                                                                             (g)    (g)  (%)                                          __________________________________________________________________________    Example 32                                                                          Reduced                                                                            110    2  17.7   9.86 98                                                 pressure                                                                Example 33                                                                          Reduced                                                                             70    2  17.8   9.27 98                                                 pressure                                                                Example 34                                                                          Reduced                                                                             50    2  18.1   9.05 97                                                 pressure                                                                Example 35                                                                          Reduced                                                                            110    5  --     7.25 95                                                 pressure                                                                __________________________________________________________________________

What is claimed is:
 1. A catalyst for producing styrene-based polymers,comprising (A) a titanium compound and (B) a contact product of a methylgroup-containing organoaluminum compound and water, wherein the contactproduct (B) has a high magnetic field component of not more than 50% inthe methyl proton signal region due to an aluminum-methyl group (Al-CH₃)bond as determined by the proton nuclear magnetic resonance absorptionmethod.
 2. A catalyst for producing styrene-based polymers, comprising(A) a titanium compound, (B) a contact product of a methylgroup-containing organoaluminum compound and water, said contact producthaving a high magnetic field component of not more than 50% in themethyl proton signal region due to an aluminum-methyl group (Al-CH₃)bond as determined by the proton nuclear magnetic resonance absorptionmethod, and (C) an organoaluminum compound.
 3. The catalyst as claimedin claim 1 wherein the high magnetic component in the methyl protonsignal region due to the aluminum-methyl group (Al-CH₃ bond asdetermined by the proton nuclear magnetic resonance absorption method isin the range of -0.1 to -0.5 ppm with the methyl proton (2.35 ppm) oftoluene under toluene solvent measuring conditions as the standard. 4.The catalyst as claimed in claim 1 wherein the contact product (B) has amolecular weight of 400 to 3,000 as determined by the freezing pointdepression method using benzene.
 5. The catalyst as claimed in claim 1wherein the contact product (B) is further subjected to heat treatmentat 30° to 200° C.
 6. The catalyst as claimed in claim 1 wherein thecontact product (B) is a contact product of trimethylaluminum andtribranched alkylaluminum represented by the formula:AlR₃ wherein R is abranched alkyl group having 3 to 10 carbon atoms, with water.
 7. Thecatalyst as claimed in claim 1 wherein the titanium compound (A) is atleast one compound selected from the group consisting of titaniumcompounds and titanium chelate compounds represented by the formula:

    TiR.sup.1.sub.a R.sup.2.sub.b R.sup.3.sub.c R.sup.4.sub.4-(a+b+c) or

    TiR.sup.1.sub.d R.sup.2.sub.e R.sup.3.sub.3-(d+e)

(wherein R¹, R², R³ and R⁴ are independently a hydrogen atom, an alkylgroup having 8 to 20 carbon atoms, an alkoxy group having 1 to 20 carbonatoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl grouphaving 6 to 20 carbon atoms, an arylalkyl group having 6 to 20 carbonatoms, an aryloxy group having 6 to 20 carbon atoms, an acyloxy grouphaving 1 to 20 carbon atoms, a cyclopentadienyl group, apentamethylcylopentadienyl group, an indenyl group or a halogen atom, a,b and c are independently an integer of 0 to 4, and d and e areindependently an integer of 0 to
 3. 8. The catalyst as claimed in claim7 wherein the catalyst comprises (A) a titanium compound, (B) a contactproduct of a methyl group-containing organoaluminum compound and water,and (c) an organoaluminum compound.